Transalkylation of aromatic hydrocarbons



TRANSALKYLATION on AROMATIC HYDROCARBONS George C. Feighner, Ponca City, Okla., assignor to Continental Oil Company, Ponca City, Okla., a corporation of Delaware Application November '13, 1956 Serial No. 621,520

sclaims. ((31.260-671) No Drawing.

ride andas such presents a disposal problem. Fnrthermore, the metal halide catalyst is deactivated in the reaction, being converted to a complex form from which its regeneration is ditficult and uneconomical. In'another proposed method alkylatable aromatics have been alkylated with isoparaflins by subjecting a mixture of such isoparaifins and aromatics to the simultaneous reaction of hydrogen fluoride and a tertiary olefin. Suitable isoparairins for use in this process must be those which contain at least one tertiary hydrogen atom per molecule.

Although the latter process is an improvement over the processes heretofore available and is in addition a one-step process whereby aromatics are alkylated with isoparaflins the results are not all that are desired. As noted above, the paraflin used must be one which contains at least one tertiary hydrogen atom per molecule.

It is therefore a principal object of this invention to provide a process which will obviate the disadvantages of the prior art processes. It is another object of my invention to provide a process whereby high molecular weight alkyl aromatic hydrocarbons may be prepared economically. It is another object of the present invention to provide a process whereby aromatic hydrocarbons may be alkylated with high molecular weight paraifins without dehydrogenating the paraflEin to an olefin or halogenating the paraifin to an alkyl halide. It is yet another advantage of my invention to provide a process which can be conducted in conventional alkylation contacters. These and other objects and advantages of the invention will become apparent as the invention is hereinafter 1. lore fully discussed.

To the accomplishment of the foregoing and related ends this invention then comprises the features hereinafter fully described and particularly pointed out in the claims. The following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however of but a few of the various ways in which the principle of the invention may be employed.

Broadly stated the present invention comprises a process for the preparation of high molecular weight alkyl aromatic hydrocarbons by transalkylation wherein the reaction is carried out in the presence of aluminum chloride and hydrogen chloride.

The process may beconsidered as comprising two steps:

United States Patent 2,914,580 Patented Nov. 24, 1959 2 (1) The alkylation of an aromatic hydrocarbon with a low molecular weight olefin:

(HC1+AlCl Where A is an aromatic radical, R is methyl and R R and R are hydrogen, methyl or ethyl, and R and R are hydrogen, or straight or branched chain alkyl groups of which the total carbon atoms of R and R total 10 to 30 or more.

The reaction might be shown electronically:

RR C=ORzR3 11 AH Brag-011mm AH Rina-011mm 11 an example, oradded directly to the high molecular" The alkylatable aromatic hydrocarbons which may be employed in the process of the present invention are those aromatic hydrocarbons which have a substitutable position on the aromatic nucleus. Such aromatic hydrocarbons include, for example, benzene, toluene, 0-, m-, and pxylenes, mixtures of xylene's, ethyl benzene, cumene, naphthalene, alpha methylnaphthalene, beta methylnaphthalene, diphenyl, the aromatics contained in hydrocarbon fractions, such as straight run fractions, and the like. Benzene is preferable.

Suitable high molecular weight paraflins for use in the processof the present invention are the various paraffin fractions which may be obtained from petroleum such as, for example, the waxes, pale oils, fuel oils, kerosene, and the like. These fractions may contain tertiary carbon atoms, but their presence in the paraflin fraction used to alkylate aromatic hydrocarbons is not essential, as is evident from the fact that normal hexadecane is suitable in the process.

Although tertiary butyl benzene is the preferred low molecular weight alkyl benzene that may be used, other low molecular Weight tertiary or secondary alkyl benzenes are also suitable, including, for example, cumene, tertiary amyl benzene, 2-ethy1 Z-phenyl butane, 2,3-dimethyl 2-phenyl butane, and Z-methyl 2-phenyl pentane. These low molecular Weight alkylbenzenes may be preared in situ from low molecular weight tertiary olefins, as

weight paraffin. When the alkyl benzenes are formed using low molecular weight tertiary olefins, suitable olefins include the following, isobutylene, propene, Z-methyl butene-l, Z-methyl butene-Z, Z-ethyl butene-2, 2,3-dimethyl butene-l, 2,3-dimethylbutene-2, and Z-methyl penten'e-l.

The ratio of reactants that may be employed in the process of my invention may be varied over a wide range. Thus, about .05 to about moles of high molecular weight paraffin and from about .05 to 1.5 moles of tertiary alkyl benzene or tertiary olefin may be used per mole of aromatic hydrocarbon. The preferred ratio of reactants per mole of aromatic hydrocarbons varies from about .1 to about .275 mole of high molecular weight paraffin and from about .1 to .5 mole of tertiary alkyl benzene or tertiary olefin.

The process of this invention may be carried out under atmospheric pressure and at temperatures of from about 50 to about 150 C. and preferably from about 75 to about 100 C. Depending on the temperature and the particular reactants employed, the reaction time may be from about one to eight hours.

In order to disclose the nature of the present invention still more clearly the following illustrative examples will be given wherein either straight or branched chain parafiin hydrocarbons are used. It is to be understood however that the invention is not to be limited to the specific conditions or details set forth in these examples except in so far as such limitations are specified in the appended claims. Parts given are parts by weight.

Example 1 146 parts of benzene, 134 parts of tertiary butyl benzene, 75.4 parts of normal hexadecane, and 15 parts of aluminum chloride were introduced into a reaction vessel equipped with an agitator, means for heating, thermometer, and reflux condenser. During the reaction a slow stream of hydrogen chloride was bubbled into the reaction mixture. The reaction mixture was heated to a temperature of 90 C., and at the end of 3 hours 29 parts of isobutane had been evolved. The reaction was then stopped, 64 parts of catalyst sludge removed, and the crude alkylate washed with sulfuric acid and aqueous sodium hydroxide. After fractional distillation there were obtained 158 parts of benzene, 39.5 parts of tertiary butyl benzene, 7.6 parts of diand poly tertiary'butyl benzene, and 61.1 parts of unreacted hexadecane. 66 parts of the desired hexadecyl-benzene was recovered.

Example 2 Example 1 was repeated with the exception that 224 parts of benzene and 56 parts of isobutylene were used Example 3 550 parts of benzene, 423 parts of tertiary butyl benzene, 350 parts of 170 SSU at 100 F. pale oil and 35 parts of aluminum chloride were introduced into a reaction vessel equipped with an agitator, means for heating, thermometer, and reflux condenser. The pale oil used herein was a solvent refined Mid-Continent oil and was dearomatized with sulfuric acid. During the reaction a slow stream of hydrogen chloride was bubbled into the reaction mixture. The reaction mixture was heated to a temperature of 88 C. and at the end of 5.5 hours 75.5 parts of isobutane had been evolved during the reaction. The reaction was then stopped, 111 parts of catalyst sludge removed, the alkylate washed with sulfuric acid and aqueous sodium hydroxide. After fractional distillation there were obtained 398 parts of henzene, and 195 parts of tertiary butyl benzene and various poly tertiary butyl benzenes. There was 81.3 partsof the desired mono alkyl benzene in 327* parts of a solu- 4 tion of the monoalkyl benzene and the unreacted'170 pale oil.

Example 4 Example 3 was repeated with the exception that 350 parts of distillate wax, a commercial product containing a high molecular weight parafiin, replaced the 170 pale oil. The distillate wax used in this example contained on an average 26 carbon atoms at a melting point of F. and a boiling range of 725-to 825 F. It was prepared by dewaxing a waxy distillate with methyl ethyl ketone. The reaction mixture was heated to a temperature of 88 C., and at the end of 7.5 hours 72 parts of isobutane had been evolved during the reaction. The reaction was then stopped, 109 parts of catalyst sludge removed, and the alkylate washed with sulfuric acid and aqueous sodium hydroxide. After fractional distillation there was obtained 565 parts of benzene, and 169 parts of tertiary butyl benzene and various poly tertiary butyl benzenes. There was 75.5 parts of monoalkyl benzene in 35 0 parts of a solution of the monoalkyl benzene and the unreacted scale wax.

Example 5 Example 5 was repeated with the exception that the 170 pale oil was replaed with 350 parts of the same type of distillate wax used in Example 4, and the benzene replaced with 920 parts of toluene. The reaction mixture was heated to a temperature of 113 C., and at the end of 6.5 hours 65.5 parts of isobutane had been evolved from the reaction mixture. The reaction was then stopped, 105 parts of catalyst sludge removed, and the alkylate washed with sulfuric acid and aqueous sodium hydroxide. After fractional distillation there was obtained 544 parts of toluene, and 204 parts of tertiary butyl toluene. There were 55 parts of monoalkyl toluene in 323 parts of the unreacted scale wax and the monoalkyl toluene.

The monoalkyl benzene may be separated from the mineral oil by physical or chemical means such as-absorption with silica gel or by sulfonation.

The procedure of Example 1 was repeated in a series of examples in which cumene and 2,3-dimethyl 2-phe1iyl" butane were substituted for tertiary butyl benzene. Simi-j lar results were obtained in all examples. In another series of examples propene and Z-methyl pentene-1 were substituted for the isobutylene employedin Example 2. Again the results were similar.

While particular embodiments of the invention have been described it will be understood of course that the invention is not limited theretosince many modifications may be made; and it is, therefore, contemplated to cover by the appended claims any such modification as fall within the true spirit and scope of the invention.

The invention having thus been described what is claimed and desired to be secured by- Letters Patent is:

1. An alkylation process'which comprises bringingfltogether in the liquid phase at atern'pe'rature' of from50 to C. an alkylatable aromatic hydrocarbon, a low mm lecular weight alkyl benzene selected from the group consisting of. secondary andtertiary alkyl benzenes,- and a high molecular weight straight chain parafiin hydrocarbon in the presence of a catalyst consisting' ofaluminum chloride and hydrogen chloride wherein: the mole ratio of said paraffin hydrocarbon to said aromatic hydrocarbon may vary from .0521 to 5:1 and the mole ratio of' said low molecular weight alkyl'benzen'e to said aromatic hydrocarbon may vary from .0511 to- 1.521 whereby said reaction mixture reacts to forma high molecular'we ight" alkyl aromatic hydrocarbon and a low molecular Weight paraffin hydrocarbon and separating said high molecular weight alkyl aromatic hydrocarbon from the reaction" mixture.

molecular weight alkyl benzene selected from the group consisting of secondary and tertiary alkyl benzenes, and a high molecular weight straight chain paraflin hydrocarbon in the presence of a catalyst consisting of aluminum chloride and hydrogen chloride wherein the mole ratio of said parafiin hydrocarbon to said aromatic hydrocarbon may vary from .05 :1 to 5:1 and the mole ratio of said low molecular weight alkyl benzene to said aromatic hydrocarbon may vary from .05 :1 to 1.5 :1 whereby said reaction mixture reacts to form a high molecular weight alkyl aromatic hydrocarbon and a low molecular weight paraflin hydrocarbon and separating said high molecular weight alkyl aromatic hydrocarbon from the reaction mixture.

3. An alkylation process which comprises bringing together in the liquid phase at a temperature of from 50 to 150 C. an alkylatable aromatic hydrocarbon, a low molecular weight alkyl benzene, selected from the group consisting of secondary and tertiary alkyl benzenes, and a high molecular weight straight chain paraffin hydrocarbon in the presence of a catalyst consisting of aluminum chloride and hydrogen chloride wherein the mole ratio of said parafiin hydrocarbon to said aromatic hydrocarbon may vary from .1 to .275 and the mole ratio of said low molecular weight alkyl benzene to said aromatic hydrocarbon may vary from .1 to .5 whereby said reaction mixture reacts to form a high molecular weight alkyl aromatic hydrocarbon and a low molecular weight parafiin hydrocarbon and separating said high molecular weight alkyl aromatic hydrocarbon from the reaction mixture.

4. The process of claim 1 wherein the alkyl benzene is tertiary butyl benzene.

5. The process of claim 1 wherein the alkyl benzene is cumene.

6. The process of claim 1 wherein the alkyl benzene is 2,-3,-dimethyl 2-phenyl butane.

7. The process of claim 1 wherein the high molecular wei ht paralfin hydrocarbon is normal hexadecane.

8. The process of claim 1 wherein the high molecular weight parafiin hydrocarbon is pale oil.

References Cited in the file of this patent UNITED STATES PATENTS 2,413,161 Zerner et a1. Dec. 24, 1946 2,737,536 Bloch et a1. Mar. 6, 1956 r 2,759,984 Schlatter Aug. 21, 1956 

1. AN ALKYLATION PROCESS WHICH COMPRISES BRINGING TOGETHER IN THE LIQUID PHASE AT A TEMPERATURE OF FROM 50 TO 150* C. AN ALKYLATABLE AROMATIC HYDROCARBON, A LOW MOLECULAR WEIGHT ALKYL BENZENE SELECTED FROM THE GROUP CONSISTING OF SECONDARY AND TERTIARY ALKYL BENZENES, AND A HIGH MOLECULAR WEIGHT STRAIGHT CHAIN PARAFFIN HYDROCARBON IN THE PRESSENCE OF A CATALYST CONSISTING OF ALUMINUM CHLORIDE AND HYDROGEN CHLORIDE WHEREIN THE MOLE RATIO OF SAID PARAFFIN HYDROCARBON TO SAID AROMATIC HYDROCARBON MAY VARY FROM .05:1 TO 5:1 AND THE MOLE RATIO OF SAID LOW MOLECULAR WEIGHT ALKYL BENZENE TO SAID AROMATIC HYDROCARBON MAY VARY FROM 05:1 TO 1.5:1 WHEREBY SIAD REACTION MIXTURE REACTS TO FORM A HIGH MOLECULAR WEIGHT ALKYL AROMATIC HYDROCARBON AND A LOW MOLECULAR WEIGHT PARAFFIN HYDROCARBON AND SEPARATING SAID HIGH MOLECULAR WEIGHT ALKYL AROMATIC HYDROCARBON FROM THE REACTION MIXTURE. 